A patient who passed gas during an operation was badly burned when the fart ignited a laser being used in the surgery, a hospital report states.

The unnamed woman, in her 30s, was undergoing surgery at Tokyo Medical University Hospital which involved a laser being applied to her cervix.

As the surgery was being carried out in the Shinjuku Ward, she broke wind — sparking the fire, Japanese newspaper the Asahi Shimbun reports.

She was left screaming in agony after the fire burned most of her body, waist and legs, according to a report by external experts into the incident, which was released on Oct. 28.

The committee stated in the report that no flammable materials were in the operating room during the surgery and that equipment was functioning normally.

“When the patient’s intestinal gas leaked into the space of the operation (room), it ignited with the irradiation of the laser, and the burning spread, eventually reaching the surgical drape and causing the fire,” the report stated.

The accident happened on April 15 this year but was only published in a recent hospital report. Tokyo Medical University Hospital is an acute care facility that claims to be the only facility in Japan to carry out surgery using robots.